DEEPEST DWELLING FISH DISCOVERED
Head 8,000 metres down into the Mariana Trench in the western Pacific and you might just bump into this guy – the Mariana snailfish, or Pseudoliparis swirei. Down on the seabed at this depth, conditions are hostile: pressure is around 1,000 times greater than at sea level, temperatures rarely reach 2°C, and it’s almost pitch black. But the Mariana snailfish, the deepest dwelling fish ever discovered, thrives where normal fish would be squashed flat.
Researchers from the University of Washington used remote controlled traps to recover 37 Mariana snailfish on two expeditions, one in 2014 and one in 2017. The snailfish family is large, with over 400 species – but few others have the impressive abilities of the Mariana snailfish.
This species has none of the fearsome features of other denizens of the deep. It’s a small, translucent creature, not even protected by scales. Despite this, it’s a top predator of the area, swallowing tiny crustaceans whole.
“This habitat would be very harsh for us, but to the Mariana snailfish, it’s home. This fish has several adaptations to help it survive under high pressure,” said researcher Dr Mackenzie Gerringer. “First, it does not have any air spaces, such as a swim bladder. Air is very compressible, so the fish would have a hard time inflating a swim bladder under such high pressure. This snailfish also has adapted enzymes and a molecule called trimethylamine oxide, which helps stabilise its proteins under pressure. There are likely other adaptations that are left to be discovered!”
“THIS FISH HAS SEVERAL ADAPTATIONS TO HELP IT SURVIVE UNDER HIGH PRESSURE”